I am trying to represent a represent a crack surface that is shared by three 3-dimensional volumes. However, I need to skip the lines and sufaces of two of the volumes ( I just need nodes on the shared surface). I tried Rjump mesher and skip by Lines, but it says "1 line has been rejected because it does not own to 2 (and only 2) HigherEntities." Could you let me know some way to get around this in GID? Also, as such I don't see an option to skip surface entities, is it possible?

it is not possible to skip surfaces when meshing using GiD. The only entities which can be skipped are points (between lines) and lines (between surfaces).For this reason, one line shared by more than two surfaces (a line with a higherentity value higher than 2) cannot be skipped, because the surfaces topology must be preserved.Depending on the geometry configuration you have, you may delete the surface you want to skip, and join the volumes it connects.